De Bruyne and Haaland were rested in the Aston Villa match. However Haaland's rest might have a different reason. His form has dropped a lot lately as you know.

I really wonder who we will see there in the first leg, Haaland or Alvarez?
Haaland has experienced a decline in performance and it seems that he can no longer be relied on in the front line and Guardiola has to place the best substitute player to replace Haaland in the front line. Against Arsenal we saw that Haaland was unable to penetrate their defense as well as other strong teams, except for Manchester city against weak teams, usually Haaland easily scores goals, it is not easy for him against a strong team like Arsenal or a team like Madrid in the UCL later in the first leg of the UCL quarter-finals.
Next season I hope Manchester City has an attacking player to replace Haaland because as we know he can no longer be relied on to be in that position because he can no longer be a goal machine for Manchester City and Guardiola must find a new player next season to replace him. In the next season, Haaland was never able to score a goal against a strong team like in the UCL last season, he couldn't even score and was able to penetrate the opponent's defense easily, always failing to score in the quarter-finals and final of the UCL last season.